Marine steering systems employing remotely actuated rotatable flexible shafts are known. These flexible means are basic elements of power transmission and are designed to transmit power or control from a driving element to an element to be driven, where direct coupling therebetween is impractical.
In known prior art marine steering systems of the class covered by this invention, the driving element is an output shaft of a device which has been appropriately "stepped-up" by suitable gearing mechanism. The stepped-up output is then fed into a rotatable flexible shaft. The driven element is usually a device which is capable of converting rotary motion from the rotatable flexible shaft to linear motion, and may comprise a ball screw cylinder, threaded screw, or the like. The linear motion is transmitted to a convenient output member which operates or controls the rudder or other steering mechanism. Such gear mechanisms are not smooth in operation, provide undesirable backlash, and are somewhat noisy even when made from suitable nonmetallic materials.
In the cross-referenced patent application, now U.S. Pat. No. 4,173,937, a pulley belt-rotatable flexible shaft device is employed which minimizes the aforementioned undesirable characteristics associated with gear mechanisms used in marine steering applications.
The present invention provides a safeguard device for use with such marine steering systems employing pulley-belt-rotatable flexible shaft means and permits immediate direct drive steering capability upon fracture of the belt means. Additionally, the present safeguard device will permit the operator of the vessel to switch to direct drive steering at high speeds of travel to thus minimize the dangers of oversteering. The changeover to direct drive is readily achieved by a simple manual operation and is available to the operator at any speed of travel of the marine vessel.